A Fourth of July fireworks show in Simi Valley, Calif., went wrong Thursday night, causing injuries to adults and children.

The number of injuries range from 14 to 24 people, according to various reports.

Cmdr. John Parks, a watch commander for the Simi Valley Police Department, told NBC Los Angeles the detonation was a "fireworks mishap" and suggested the explosion was accidental. The TV station reports 20 were injured.

Annisa Wynn, who was at the show, told KTLA-TV Channel 5 - which reported 14 were injured - the explosion happened about two minutes into the show. The fireworks suddenly began shooting sideways along the ground into the crowd instead of up in the air, she said.

“The fireworks were so close, you could see them on the ground," Wynn said. "It never happens this way. People were screaming."

The Los Angeles Times reported "at least 14" were injured. According to its report, Ventura County firefighters set up a triage center in the park, where they treated adults and children, many of them hit by flying debris.

"There was a big boom, everybody started running down the street, people were screaming,” Justice Allen, 17, told The Times. "Everybody was just terrified. People hid in bushes."

The Associated Press reports Jordan Roberts, a public safety dispatcher with the Ventura County Fire Department, said more than a dozen people were being taken to area hospitals with minor to moderate injuries.